High melt temperature microporous lithium-ion rechargeable battery separators and methods of preparation and use

ABSTRACT

Disclosed or provided are high melt temperature microporous Lithium-ion rechargeable battery separators, shutdown high melt temperature battery separators, battery separators, membranes, composites, and the like that preferably prevent contact between the anode and cathode when the battery is maintained at elevated temperatures for a period of time, methods of making, testing and/or using such separators, membranes, composites, and the like, and/or batteries, Lithium-ion rechargeable batteries, and the like including one or more such separators, membranes, composites, and the like.

RELATED APPLICATIONS

This application is a U.S. Application which claims priority to and thebenefit of U.S. Provisional Patent App. No. 61,369,907, filed Aug. 2,2010, and U.S. Provisional Application No. 61/369,959, filed Aug. 2,2010, which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention is directed to high melt temperature microporous batteryseparators, high melt temperature microporous Lithium-ion rechargeablebattery separators, shutdown battery separators, battery separators,membranes, composites, components, and the like that preferably preventcontact between the anode and cathode when the battery is maintained atelevated temperatures for a period of time, to methods of making,testing and/or using such separators, membranes, composites, components,and the like, and/or to Lithium-ion batteries, Lithium-ion rechargeablebatteries, batteries, and the like including one or more suchseparators, membranes, composites, and the like. At least selectedembodiments are directed to high melt temperature coated microporousLithium-ion rechargeable battery separators, to high melt temperaturemicroporous Lithium-ion rechargeable electrospun coated batteryseparators, electrospun separator membranes, and the like, to methods ofmaking and/or using such coated separators, electrospun coatedseparators, electrospun separator membranes, and the like, and/or toLithium-ion rechargeable batteries including one or more such coatedseparators, electrospun coated separators, separator membranes, and thelike.

BACKGROUND OF THE INVENTION

Manufacturers of Lithium-ion batteries strive to produce Lithium-ionrechargeable batteries that shutdown under certain extreme conditionsand at high temperatures.

Although battery separators are well known, such as high quality,polyolefin, Lithium-ion rechargeable battery separators manufactured andsold by Celgard, LLC of Charlotte, N.C., there is a need for improved ornovel battery separators for at least certain extreme conditions, hightemperatures, high melt temperature microporous battery separators, highmelt temperature microporous Lithium-ion rechargeable batteryseparators, membranes, composites, components, and the like thatpreferably prevent contact between the anode and cathode when thebattery is maintained at elevated temperatures for a period of time,methods of making, testing and/or using such separators, membranes,composites, components, and the like, and/or Lithium-ion batteries,Lithium-ion rechargeable batteries, batteries, and the like includingone or more such separators, membranes, composites, and the like.

Also, there is a need for improved or novel battery separators for atleast certain high temperature applications, for high melt temperaturecoated microporous Lithium-ion rechargeable battery separators, highmelt temperature microporous Lithium-ion rechargeable electrospun coatedbattery separators, electrospun separator membranes, and the like, tomethods of making and/or using such coated separators, electrospuncoated separators, electrospun separator membranes, and the like, and/orto Lithium-ion rechargeable batteries including one or more such coatedseparators, electrospun coated separators, electrospun separatormembranes, and the like.

SUMMARY OF THE INVENTION

At least certain embodiments of the present invention may address theneed for improved or novel battery separators for at least certainextreme conditions, high temperatures, high melt temperature microporousbattery separators, high melt temperature microporous Lithium-ion(Li-ion) rechargeable battery separators, battery separators, membranes,films, composites, and the like that preferably prevent contact betweenthe anode and cathode when the battery is maintained at elevatedtemperatures for a period of time, methods of making, testing and/orusing such separators, membranes, composites, components, and the like,and/or Lithium-ion batteries, Lithium-ion rechargeable batteries, otherbatteries, and the like (including batteries, cells, packs,accumulators, capacitors, or the like) including one or more suchseparators, membranes, composites, and/or the like. Such Lithium-ionbatteries, or other batteries, cells, packs, or the like may be of anyshape, size and/or configuration, such as cylindrical, flat,rectangular, large scale such as large scale Electric Vehicle (EV),prismatic, button, envelope, box, and/or the like.

At least selected embodiments of the invention are directed to high melttemperature microporous Lithium-ion rechargeable battery separators,membranes, films, composites, components, and the like that preferablyprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time, to methods ofmaking, testing and/or using such separators, membranes, composites,components, and the like, and/or to Lithium-ion rechargeable batteriesincluding one or more such separators, membranes, composites, and/or thelike.

At least certain embodiments are directed to improved or novel batteryseparators for at least certain high temperature applications, to highmelt temperature coated microporous Lithium-ion rechargeable batteryseparators, to high melt temperature microporous Lithium-ionrechargeable electrospun coated battery separators, to electrospunseparator membranes, to methods of making and/or using such coatedseparators, electrospun separators, electrospun membranes, and/or toLithium-ion rechargeable batteries including one or more such coatedseparators, electrospun coated separators, electrospun separatormembranes, and/or the like.

Manufacturers of Lithium-ion batteries are striving to achieve aLithium-ion rechargeable battery that is capable of at least partialfunctioning at high temperatures (for example, at about 160 degreesCentigrade (deg C) or Celsius, preferably at about 180 deg C., morepreferably at about 200 deg C., most preferably at about 220 deg C. orhigher) for at least a short period of time. Such partial functioningpreferably includes at least keeping the electrodes (anode and cathode)physically separated at high temperatures for at least a short period oftime, and may also include shutdown or shut down, full shutdown, partialshutdown, allowing or providing at least partial ionic flow between theelectrodes, or even full ionic flow. For example, one layer of theseparator may shutdown at about 130 deg C., but another layer of theseparator preferably keeps the electrodes (anode and cathode) physicallyseparated for at least 5 minutes, preferably 15 minutes, and morepreferably for 60 minutes, at about 160 deg C., preferably at about 180deg C., more preferably at about 200 deg C., most preferably at about220 deg C. or higher, this is partial functioning at high temperature.In another embodiment, a possibly preferred separator keeps theelectrodes (anode and cathode) physically separated for at least 5minutes, preferably for at least 15 minutes, and more preferably for atleast 60 minutes, and provides full shutdown (no ionic flow) between theelectrodes at about 160 deg C. (for example, shuts down at 130 deg C.).In another embodiment, a possibly preferred separator keeps theelectrodes (anode and cathode) physically separated for at least 5minutes, preferably for at least 15 minutes, and more preferably for atleast 60 minutes, at about 180 deg C. In another embodiment, a possiblypreferred separator keeps the electrodes (anode and cathode) physicallyseparated for at least 5 minutes, preferably for at least 15 minutes,and more preferably for at least 60 minutes, at about 200 deg C. Inanother embodiment, a possibly most preferred separator keeps theelectrodes (anode and cathode) physically separated for at least 5minutes, preferably for at least 15 minutes, and more preferably for atleast 60 minutes, at about 250 deg C. or more.

A possibly preferred high temperature separator has at least one layeror component that has a high melt temperature, preferably >160 deg C.,more preferably >180 deg C., still more preferably >200 deg C., and mostpreferably >220 deg C., and has a high level of dimensional orstructural integrity needed to prevent contact between the anode andcathode when the battery is maintained at elevated temperatures for aperiod of time, preferably for at least 5 minutes, more preferably forat least 15 minutes, and still more preferably for at least 60 minutes,and may optionally preferably shutdown at 130 deg C.

A possibly more preferred high temperature separator has a high melttemperature, preferably >180 deg C. and more preferably >200 deg C., andhas a high level of dimensional or structural integrity needed toprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time.

A possibly most preferred high temperature separator has at least onelayer including a polymer with a glass transition temperature (Tg) ofabout 250 deg C. or more (a high Tg polymer) and with a Tg suppressionin electrolyte of about 50 deg C. or less (an effective Tg of about 200deg C. or more in electrolyte), and has at least one layer having a highlevel of dimensional or structural integrity sufficient to preventcontact between the anode and cathode when the battery is maintained atelevated temperatures for a period of time. The high Tg polymer shouldalso be dissolvable in at least one solvent or solvent mixture, andpreferably the high Tg polymer is soluble in at least one moderatelyvolatile solvent, such as DMAc.

In accordance with at least certain embodiments, it is highly desirableto have a high melt temperature separator with at least one layer havinga high level of dimensional or structural integrity (preferably both)sufficient to prevent contact between the anode and cathode when thebattery is maintained at elevated temperatures, preferably >160 deg C.,more preferably >180 deg C., still more preferably >200 deg C., and mostpreferably >220 deg C., for a period of time, preferably for at least 5minutes, more preferably for at least 15 minutes, and still morepreferably for at least 60 minutes, and may optionally provideshut-down, preferably at about 120 deg C., more preferably at 125 degC., most preferably at 130 deg C. Such a separator may be referred to asa high temperature melt integrity (HTMI) separator with shutdown.

In accordance with at least selected embodiments, the possibly preferredinventive separator is either a high melt temperature battery separatorincluding a porous membrane coated with a high glass transitiontemperature (Tg) polymer or blend (also referred to as a binder whenused with filler or particles) on at least one side thereof or a standalone (single or multi-ply) porous membrane having at least one layermade using a high Tg polymer or blend. Possibly preferred is a non-heatset, high Tg polymer or blend. The high Tg polymer should also bedissolvable in at least one solvent or solvent mixture, and preferablythe high Tg polymer is soluble in at least one moderately volatilesolvent, such as DMAc.

A possibly most preferred high temperature separator has at least onelayer including a high Tg polymer with a glass transition temperature(Tg) of about 250 deg C. or more and with a Tg suppression inelectrolyte of about 50 deg C. or less (an effective Tg of about 200 degC. or more in electrolyte), and has a high level of dimensional orstructural integrity needed to prevent contact between the anode andcathode when the battery is maintained at elevated temperatures for aperiod of time. The preferred high Tg polymer should also be dissolvablein at least one solvent or solvent mixture, and preferably the high Tgpolymer is soluble in at least one moderately volatile solvent.

In accordance with selected embodiments, at least one object of thepresent invention is to provide a high melt temperature microporousLithium-ion rechargeable battery separator, membrane, film or compositethat has at least one layer, component, or coating that is capable ofretaining its physical structure up to 200 deg C., preferably up to 250deg C., in a Lithium-ion rechargeable battery (battery, cell, pack,accumulator, capacitor, or the like) for at least a short period oftime. This particular possibly preferred separator, membrane orcomposite includes at least one layer preferably composed of orincluding one or more polymers which have an effective glass transitiontemperature (T_(g)) in electrolyte greater than 160 deg C., morepreferably greater than 180 deg C., and most preferably at least 200 degC. Preferably, the separator, membrane or composite includes a polymer,blend or combination of polymers having a glass transition temperature(T_(g)) of at least 250 deg C., such as but not limited to,polyimidazoles, polybenzimidazole (PBI), polyimides, polyamideimides,polyaramids, polysulfones, aromatic polyesters, polyketones, and/orblends, mixtures, and combinations thereof. The possibly preferredseparator, membrane or composite may include or be composed of a singleor double sided high Tg polymer microporous coating (with or withouthigh temperature fillers or particles) applied to a microporous basemembrane or film. Alternatively, the possibly preferred separator ormembrane may be a free standing high Tg polymer microporous separator ormembrane (with or without high temperature fillers or particles). Yetanother possibly preferred separator, membrane or composite may includeat least one high Tg polymer microporous layer (with or without hightemperature fillers or particles).

Still yet another preferred separator may include or be composed of anelectrospun coated, single or double sided, high Tg polymer microporouscoating applied to a microporous base membrane or film. In accordancewith at least selected embodiments, a possibly preferred inventiveseparator is a high melt temperature battery separator consisting of aporous membrane with an electrospun nanofiber coating of a high glasstransition temperature (Tg) polymer, preferably Polybenzimidazole (PBI)or a blend of PBI with other polymer or polymers, on at least one sidethereof and preferably coated on two sides. Although PBI may bepreferred, a blend of PBI with another polymer or other polymers such aspolyaramids, polyimides, polyamideimide, polyvinylidene fluoride,co-polymers of polyvinylidene fluoride and blends, mixtures and/orcombinations thereof may also be used.

In accordance with selected embodiments, at least one object of thepresent invention is to provide a high melt temperature coated orelectrospun coated microporous Lithium-ion rechargeable batteryseparator or membrane that is capable of retaining its physicalstructure up to 250 deg C. in a Lithium-ion rechargeable battery (cell,pack, battery, accumulator, capacitor, or the like) for at least a shortperiod of time. This particular possibly preferred separator or membranepreferably has an electrospun nanofiber coating of polybenzimidazole(PBI) or a blend of PBI with another polymer or other polymers appliedto at least one side thereof and preferably coated on two sides of amicroporous base membrane. The preferred electrospun nanofiber coatingconsists of nanoscale PBI fibers which are in the range of 10 to 2,000nanometers in diameter, preferably 20 to 1,000 nanometers in diameter,more preferably 25 to 800 nanometers in diameter, and most preferably 30to 600 nanometers in diameter. The preferred targeted basis weight ofthe nanoscale PBI electrospun coating of the high melt temperaturemicroporous Lithium-ion rechargeable battery separator membrane is 1.0to 8.0 g/m² or more, preferably 2.0 to 6.0 g/m², more preferably 2.2 to5.0 g/m², and most preferably 2.5 to 5.0 g/m². The preferred fibers aresmooth when viewed by SEM at 5,000× magnification and are non-porous.The electrospinning process can deposit nanoscale PBI fibers on thesurface of a base microporous membrane in a random fashion resemblingspaghetti noodles scattered on a surface.

The electrospinning coating approach can coat a high Tg polymer such asPBI or a blend of PBI with another polymer or polymers such aspolyaramids, polyimides and polyamideimide and blends, mixtures and/orcombinations thereof onto a microporous porous membrane without adetrimental affect to the pore structure or the porosity of the porousbase membrane, that is, the nanoscale electrospun fibers do not blockthe pores of the base membrane. The electrospinning process provides amethod of applying a high Tg polymer in the form of nanoscale fibersonto a microporous base membrane without the nanoscale fibers themselvesrequired to be porous. The spaces between the fibers provide thenecessary openings or porosity. A process step to form pores in theelectrospun nanoscale high Tg polymer fibers is not required. In theelectrospinning process, the high Tg polymers or polymers are dissolvedin a solvent or solvents. The solvent is evaporated during the formationof the electrospun fibers. Typically, dip coated or gravure coatedmethods of applying polymers onto a microporous base membrane mayrequire the coated film to be immersed in a bath designed for removingthe polymer solvent. The present electrospinning method of applying highTg polymers onto microporous membranes or for forming stand alonemembranes may be simpler than other processes from a manufacturing pointof view because an immersion step or extraction step to remove thesolvent in order to form a porous structure in the coating is notrequired. Electrospinning can be a less costly manufacturing process forthe application of nanoscale high Tg polymer fibers onto a microporousmembrane to produce a high melt temperature microporous Lithium-ionrechargeable battery separator or membrane.

In at least selected separator or membrane embodiments, the high Tgpolymer can be coated onto a microporous base membrane made of athermoplastic polymer provided the high Tg polymer is soluble in atleast one moderately volatile solvent. Thermoplastic polymers include,but are not limited to, polyolefins such as polyethylene, polypropylene,polymethylpentene, and/or blends, mixtures, or combinations thereof.Such polyolefin microporous base membranes are available from Celgard,LLC of Charlotte, N.C. The microporous base membranes can bemanufactured by, for example, a dry stretch process (known as theCelgard® dry stretch process) of Celgard, LLC of Charlotte, N.C., or bya wet process also known as a phase separation or extraction process ofCelgard Korea Inc. of South Korea, Asahi of Japan and Tonen of Japan.The base membrane may be a single layer (one or more plies) ofPolypropylene or Polyethylene, or a multi-layer membrane, such as atri-layer membrane e.g., Polypropylene/Polyethylene/Polypropylene(PP/PE/PP) or Polyethylene/Polypropylene/Polyethylene (PE/PP/PE),bi-layer membrane (PP/PE or PE/PP), or the like.

Some base membranes or films, such as Polypropylene, may requirepre-treatment in order to alter the surface characteristics of themembrane and improve the adhesion of the high Tg polymer coating ornanoscale electrospun fibers to one or both sides of the base membrane.Pre-treatments may include, but are not limited to, priming, stretching,corona treatment, plasma treatment, and/or coating, such as surfactantcoatings on one or both sides thereof.

BRIEF DESCRIPTION OF DRAWINGS

For the purposes of illustrating the various embodiments or aspects ofthe invention, there is shown in the drawings a form that is presentlyexemplary; it being understood, however, that the invention is notlimited to the embodiments, precise arrangements or instrumentalitiesshown.

FIG. 1 is a schematic side view of one embodiment of the present coatingprocess and film path.

FIG. 2 is schematic of typical Hot ER (Electrical Resistance)thermogram.

FIG. 3 is schematic side view of Hot Tip Hole propagation test setup.

FIG. 4 is an Expansion Thermomechanical Analysis (e-TMA) thermogram ofthe 13 μm Control (uncoated) base membrane and the five coatedembodiments included as present Examples 1-5.

FIG. 5 is a Hot Electrical Resistance (Hot ER) thermogram of the 13 μmControl and present Examples 1-4.

FIG. 6 shows six respective top view digital images of Hot Tip Holepropagation test results conducted on the 13 μm Control (uncoated) basemembrane and the five coated embodiments included as present Examples1-5 with hole diameters indicated.

FIG. 7 is a surface SEM micrograph view at 5,000× magnification ofpresent Example 4.

FIG. 8 is a cross section SEM micrograph at 10,000× magnification ofpresent Example 4.

FIG. 9 is a surface SEM micrograph at 5,000× magnification of presentExample 3.

FIG. 10 is a cross section SEM micrograph at 5,000× magnification ofpresent Example 3.

FIG. 11 is a cross section SEM micrograph at 5,200× magnification of thecoating in present Example 5.

FIG. 12 is an Expansion Thermomechanical Analysis (e-TMA) thermogram ofthe 16 μm Control Sample and present Examples 6 and 2.

FIG. 13 is a thermogram of a Hot Electrical Resistance (Hot ER) test onthe 16 μm Control Sample and present Examples 6 and 2.

FIG. 14 are respective Hot Tip Hole propagation digital images of the 16μm Control Sample and present Examples 6 and 2.

FIG. 15 is a surface SEM micrograph at 20,000× magnification of presentExample 6.

FIG. 16 are respective cross section SEM micrographs (left image) at830× magnification and (right image) at 2,440× magnification of presentExample 6.

FIG. 17 is a surface SEM micrograph at 20,000× magnification of presentExample 2.

FIG. 18 are respective cross section SEM micrographs at a magnificationof 2,980× (left image) and at a magnification of 13,300× (right image)of present Example 2.

FIG. 19 are additional respective cross section SEM micrographs at amagnification of 4,380 (left image) and at a magnification of 12,100×(right image) of present Example 2.

FIG. 20 is a schematic of an electrospinning device showing fiberformation.

FIG. 21 is a SEM micrograph showing surface view of PBI electrospuncoating at 5,000× magnification.

FIG. 22 is a SEM micrograph showing surface view of PBI electrospuncoating at 20,000× magnification.

FIG. 23 is a Hot Tip Hole Propagation Control sample image with holediameter=2.96 mm

FIG. 24 is a Hot Tip Hole Propagation 1-sided PBI coated sample imagewith hole diameter=0.68 mm.

FIG. 25 is a Hot Tip Hole Propagation 2-side PBI coated sample imagewith hole diameter=0.595 mm.

FIG. 26 is a Hot ER Thermogram of Uncoated control sample, 1-sided PBIcoated and 2-sided PBI coated Celgard membrane.

FIG. 27 is an Extension-TMA Thermogram of Uncoated control sample,1-sided PBI coated and 2-sided PBI coated Celgard membrane.

FIG. 28 is a Hot ER Thermogram of Surfactant coated Celgard®3401 controlsample and 2-sided PBI coated Celgard®3401 membrane.

FIG. 29 is an Extension-TMA Thermogram of Surfactant coated Celgard®3401 control sample and 2-sided PBI coated Celgard® 3401 membrane.

FIG. 30 is a Hot Tip Hole Propagation Celgard® 3401 surfactant coatedsample image with hole diameter=3.7 mm.

FIG. 31 is a Hot Tip Hole Propagation PBI electropsun coated sampleimage with hole diameter=0.596 mm.

DETAILED DESCRIPTION OF THE INVENTION

At least certain embodiments of the present invention may address theneed for improved or novel battery separators for at least certainextreme conditions, high temperatures, high melt temperature microporousbattery separators, high melt temperature microporous Lithium-ionrechargeable battery separators, battery separators, membranes, films,composites, and the like that preferably prevent contact between theanode and cathode when the battery is maintained at elevatedtemperatures for a period of time, methods of making, testing and/orusing such separators, membranes, composites, components, and the like,and/or Lithium-ion batteries, Lithium-ion rechargeable batteries, otherbatteries, and the like (including batteries, cells, packs,accumulators, capacitors, or the like) including one or more suchseparators, membranes, composites, and the like. Such Lithium-ionbatteries, or other batteries, cells, packs, or the like may be of anyshape, size and/or configuration, such as cylindrical, flat,rectangular, large scale such as large scale Electric Vehicle (EV),prismatic, button, envelope, box, and/or the like.

At least selected embodiments of the invention are directed to high melttemperature microporous Lithium-ion rechargeable battery separators,membranes, composites, components, and the like that preferably preventcontact between the anode and cathode when the battery is maintained atelevated temperatures for a period of time, to methods of making,testing and/or using such separators, membranes, composites, components,and the like, and/or to Lithium-ion rechargeable batteries including oneor more such separators, membranes, composites, and the like.

Manufacturers of Lithium-ion batteries are striving to achieve aLithium-ion rechargeable battery that is capable of at least partialfunctioning at high temperatures (for example, at about 160 degreesCentigrade (deg C) or Celsius, preferably at about 180 deg C., morepreferably at about 200 deg C., most preferably at about 220 deg C. orhigher) for at least a short period of time. Such partial functioningpreferably includes at least keeping the electrodes (anode and cathode)physically separated at high temperatures for at least a short period oftime, and may also include shutdown, full shutdown, partial shutdown,allowing or providing at least partial ionic flow between theelectrodes, or even full ionic flow. For example, one layer of theseparator may shutdown at about 130 deg C., but another layer of theseparator preferably keeps the electrodes (anode and cathode) physicallyseparated for at least 5 minutes, preferably 15 minutes, and morepreferably for 60 minutes, at about 160 deg C., preferably at about 180deg C., more preferably at about 200 deg C., most preferably at about220 deg C. or higher, this is partial functioning at high temperature.In another embodiment, a possibly preferred separator keeps theelectrodes (anode and cathode) physically separated for at least 5minutes, preferably for at least 15 minutes, and more preferably for atleast 60 minutes, and provides full shut-down (no ionic flow) betweenthe electrodes at about 160 deg C. (for example, shuts down at 130 degC.). In another embodiment, a possibly preferred separator keeps theelectrodes (anode and cathode) physically separated for at least 5minutes, preferably for at least 15 minutes, and more preferably for atleast 60 minutes, at about 180 deg C. In another embodiment, a possiblypreferred separator keeps the electrodes (anode and cathode) physicallyseparated for at least 5 minutes, preferably for at least 15 minutes,and more preferably for at least 60 minutes, at about 200 deg C. Inanother embodiment, a possibly most preferred separator keeps theelectrodes (anode and cathode) physically separated for at least 5minutes, preferably for at least 15 minutes, and more preferably for atleast 60 minutes, at about 250 deg C. or more.

A possibly preferred high temperature separator has at least one layer,coating or component that has a high melt temperature, preferably >160deg C., more preferably >180 deg C., still more preferably >200 deg C.,and most preferably >220 deg C., and has a high level of dimensional orstructural integrity needed to prevent contact between the anode andcathode when the battery is maintained at elevated temperatures for aperiod of time, preferably for at least 5 minutes, preferably for atleast 15 minutes, and more preferably for at least 60 minutes, and mayoptionally preferably shutdown at 130 deg C.

A possibly more preferred high temperature separator has a high melttemperature, preferably >180 deg C. and more preferably >200 deg C., andhas a high level of dimensional or structural integrity needed toprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time.

A possibly most preferred high temperature separator has at least onelayer including a polymer with a glass transition temperature (Tg) ofabout 250 deg C. or more (a high Tg polymer) and with a Tg suppressionin electrolyte of about 50 deg C. or less (an effective Tg of about 200deg C. or more in electrolyte), and has at least one layer having a highlevel of dimensional or structural integrity sufficient to preventcontact between the anode and cathode when the battery is maintained atelevated temperatures for a period of time. The high Tg polymer shouldalso be dissolvable in at least one solvent or solvent mixture, andpreferably the high Tg polymer is soluble in at least one moderatelyvolatile solvent, such as DMAc.

In accordance with at least certain embodiments, it is highly desirableto have a high melt temperature separator with at least one layer orcoating having a high level of dimensional or structural integrity(preferably both) sufficient to prevent contact between the anode andcathode when the battery is maintained at elevated temperatures,preferably >160 deg C., more preferably >180 deg C., still morepreferably >200 deg C., and most preferably >220 deg C., for a period oftime, preferably for at least 5 minutes, preferably for at least 15minutes, and more preferably for at least 60 minutes, and may optionallyprovide shut-down, preferably at about 120 deg C., more preferably at125 deg C., most preferably at 130 deg C. Such a separator may bereferred to as a high temperature melt integrity (HTMI) separator.

In accordance with at least selected embodiments, the possibly preferredinventive separator is either a high melt temperature battery separatorincluding a porous membrane coated with a high glass transitiontemperature (Tg) polymer or blend (also referred to as a binder whenused with filler or particles) on at least one side thereof or a standalone (single or multi-ply) porous membrane having at least one layermade using a high Tg polymer or blend. Possibly preferred is a non-heatset, high Tg polymer or blend. The high Tg polymer should also bedissolvable in at least one solvent or solvent mixture, and preferablythe high Tg polymer is soluble in at least one moderately volatilesolvent, such as DMAc.

A possibly most preferred high temperature separator has at least onelayer or coating including a high Tg polymer with a glass transitiontemperature (Tg) of about 250 deg C. or more and with a Tg suppressionin electrolyte of about 50 deg C. or less (an effective Tg of about 200deg C. or more in electrolyte), and has a high level of dimensional orstructural integrity needed to prevent contact between the anode andcathode when the battery is maintained at elevated temperatures for aperiod of time. The preferred high Tg polymer should also be dissolvablein at least one solvent or solvent mixture, and preferably the high Tgpolymer is soluble in at least one moderately volatile solvent.

In accordance with selected embodiments, at least one object of thepresent invention is to provide a high melt temperature microporousLithium-ion rechargeable battery separator, membrane or composite thathas at least one layer or coating that is capable of retaining itsphysical structure up to 200 deg C., preferably up to 250 deg C., in aLithium-ion rechargeable battery (battery, cell, pack, accumulator,capacitor, or the like) for at least a short period of time. Thisparticular possibly preferred separator, membrane or composite includesat least one layer or coating preferably composed of or including one ormore polymers which have an effective glass transition temperature(T_(g)) in electrolyte greater than 160 deg C., more preferably greaterthan 180 deg C., and most preferably at least 200 deg C. Preferably, theseparator, membrane or composite includes a polymer, blend orcombination of polymers having a glass transition temperature (T_(g)) ofat least 250 deg C., such as but not limited to, polyimidazoles,polybenzimidazole (PBI), polyimides, polyamideimides, polyaramids,polysulfones, aromatic polyesters, polyketones, and/or blends, mixtures,and combinations thereof. The possibly preferred separator, membrane orcomposite may include or be composed of a single or double sided high Tgpolymer microporous coating (with or without high temperature fillers orparticles) applied to a microporous base membrane or film.Alternatively, the possibly preferred separator or membrane may be afree standing high Tg polymer microporous separator or membrane (with orwithout high temperature fillers or particles). Yet another possiblypreferred separator, membrane or composite may include at least one highTg polymer microporous layer (with or without high temperature fillersor particles).

In at least selected separator or membrane embodiments, the high Tgpolymer can be coated onto a microporous base membrane made of athermoplastic polymer provided the high Tg polymer is soluble in atleast one moderately volatile solvent. Thermoplastic polymers include,but are not limited to, polyolefins such as polyethylene, polypropylene,polymethylpentene, and/or blends, mixtures, or combinations thereof.Such polyolefin microporous base membranes are available from Celgard,LLC of Charlotte, N.C. The microporous base membranes can bemanufactured by, for example, a dry stretch process (known as theCelgard® dry stretch process) of Celgard, LLC of Charlotte, N.C., or bya wet process also known as a phase separation or extraction process ofCelgard Korea Inc. of South Korea, Asahi of Japan and Tonen of Japan.The base membrane may be a single layer (one or more plies) ofPolypropylene or Polyethylene, or a multi-layer membrane, such as atri-layer membrane e.g., Polypropylene/Polyethylene/Polypropylene(PP/PE/PP) or Polyethylene/Polypropylene/Polyethylene (PE/PP/PE),bi-layer membrane (PP/PE or PE/PP), or the like.

Some base membranes or films, such as Polypropylene, may requirepre-treatment in order to alter the surface characteristics of themembrane and improve the adhesion of the high Tg polymer coating to oneor both sides of the base membrane. Pre-treatments may include, but arenot limited to, priming, stretching, corona treatment, plasma treatment,and/or coating, such as surfactant coatings on one or both sidesthereof.

At least certain objects of the present invention are directed tobattery separators for at least certain extreme conditions, hightemperatures, high melt temperature microporous battery separators, highmelt temperature microporous Lithium-ion rechargeable batteryseparators, battery separators, separator membranes, and the like thatpreferably prevent contact between the anode and cathode when thebattery is maintained at elevated temperatures for a period of time,methods of making, testing and/or using such separators, membranes, andthe like, and/or Lithium-ion batteries, Lithium-ion rechargeablebatteries, batteries, cells, packs, accumulators, capacitors, and thelike including one or more such separators, membranes, and the like.Such batteries, cells, packs, or the like may be of any shape, sizeand/or configuration, such as cylindrical, flat, rectangular, largescale, large scale Electric Vehicle (EV), prismatic, button, envelope,box, wound, folded, z-fold, and/or the like.

At least certain objects of the invention are directed to high melttemperature microporous Lithium-ion rechargeable battery separators,membranes, and the like that preferably prevent contact between theanode and cathode when the battery is maintained at elevatedtemperatures for a period of time, to methods of making, testing and/orusing such separators, membranes, and the like, and/or to Lithium-ionrechargeable batteries including one or more such separators, membranes,and the like.

At least selected embodiments of the invention are directed to high melttemperature microporous Lithium-ion battery separators that preferablyprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time, to methods ofmaking and/or using such separators, and/or to Lithium-ion rechargeablebatteries including one or more such separators.

In accordance with selected embodiments, at least one object of thepresent invention is to provide a high melt temperature microporousbattery separator or membrane that is capable of retaining its physicalstructure up to 250 deg C. in a battery, cell, pack, accumulator,capacitor, or the like. This particular possibly preferred separator ormembrane is preferably composed of one or more polymers which have aglass transition temperature (T_(g)) greater than 165 deg C. including,more preferably a polymer, blend or combination which has a glasstransition temperature (T_(g)) greater than 180 deg C., most preferablywhich has a glass transition temperature (T_(g)) greater than 250 degC., such as but not limited to, polyimidazoles, polybenzimidazole (PBI),polyimides, polyamideimides, polyaramids, polysulfones, aromaticpolyesters, polyketones, and/or blends, mixtures, and combinationsthereof. The possibly preferred separator or membrane can be composed ofa single or double sided high Tg polymer coating applied to amicroporous base membrane or can be a free standing high Tg polymermicroporous separator or membrane. The high Tg polymer may be filled orunfilled. The high Tg polymer can be coated onto a microporous basemembrane made of a thermoplastic polymer and preferably the high Tgpolymer is soluble in at least one moderately volatile solvent.Thermoplastic polymers include, but are not limited to, polyolefins suchas polyethylene, polypropylene, polymethylpentene, and blends, mixtures,or combinations thereof. The base membrane may be a single layer (one ormore plies) or multi-layer membrane, such as a tri-layer membrane e.g.,Polypropylene/Polyethylene/Polypropylene (PP/PE/PP) orPolyethylene/Polypropylene/Polyethylene (PE/PP/PE), bi-layer membrane(PP/PE or PE/PP), or the like.

Some base membranes or films, such as Polypropylene, may requirepre-treatment in order to alter the surface characteristics of themembrane and improve the adhesion of the high Tg polymer coating to thebase membrane. Pre-treatments may include, but are not limited to,priming, stretching, corona treatment, plasma treatment, and/or coating,such as surfactant coatings on one or both sides thereof.

In accordance with at least one embodiment, an object of the inventionis to provide a high melt temperature microporous separator that iscapable of retaining its physical structure up to 250 deg C. in a hightemperature battery.

In accordance with at least selected embodiments, the high Tg polymermay be applied in a coating solution by a coating slot die (see FIG. 1),a doctor blade, a Meyer rod, or a direct or reverse gravure type roll. Acoating solution may be prepared by dissolving the high T_(g) polymer ina suitable solvent, for example, Dimethylacetamide (DMAc),N-methylpyrrolidinone, 1,4 dioxane, acetone, etc. The coating solutionmay further contain 1) a non-solvent for the high Tg polymer, 2) a crosslinking agent such as a dihalide, dialdehyde or acid dichloride, 3) asurfactant to improve coating uniformity, 4) inorganic particles such asAl₂O₃, TiO₂, CaCO₃, BaSO₄, silica carbide, boron nitride, or 5) organicpolymers such as powdered PTFE, or other chemically inert, small(preferably less than 2 microns, more preferably less than 1 micron),dry, and high melt temperature.

Following application of the high Tg polymer, the membrane may beimmersed in a gelation bath (see FIG. 1). The gelation bath may consistof a single bath comprised of a non-solvent or a mixture of non-solventsor the gelation bath may consist of a series of baths which includemixtures of a solvent and one or more non-solvents. In the case wherethe coating operation consists of a series of baths, the final bathshould consist of a non-solvent or mixtures of non-solvents. It shouldbe noted that the distance between the coating die and the gelation bathshould be minimized in order to prevent contact of the coating mixturewith the air. The bath may be at room temperature, below roomtemperature or at an elevated temperature.

The gelation bath step serves to precipitate the high Tg polymer ontothe base membrane, remove the polymer solvent (or solvents) and createthe porous structure in the high Tg polymer coating or layer. The choiceof bath composition and the temperature of the bath controls the rate ofprecipitation of the polymer and the porosity and pore structure of theporous coating or layer formed on the base membrane, film or carrier.

The coated membrane, film or carrier may then be dried in an oven andcan be dried on a tenter frame to prevent shrinkage or curling of thefilm. The final high Tg polymer coating or layer thickness maypreferably be 1-20 μm with the coated microporous membrane or separatorhaving a total thickness of preferably 5-40 μm. In at least certainpossibly preferred embodiments, it may be preferred to have a coating ofat least about 4 μm, preferably at least about 6 μm, more preferably atleast about 8 μm on at least one side, preferably on both sides, of apolyolefin microporous membrane to form an HTMI separator.

Another possibly preferred inventive separator is an electrospun coatedmicroporous battery separator, having an electrospun nanofiber coatingof a high glass transition temperature (Tg) polymer preferablyPolybenzimidazole (PBI) on at least one side thereof and preferablycoated on two sides (on both sides of the porous base film). AlthoughPBI may be preferred, a blend of PBI with other polymer or polymers suchas polyaramids, polyimides, polyamideimide, polyvinyldiene fluoride andco-polymers of polyvinylidene fluoride and blends, mixtures and/orcombinations thereof may also be used.

Electrospinning is a process that can be used to create polymericnanofibers in the range of 40-2,000 nm. The electrospinning process usesan electric field to draw a polymer solution from the tip of a capillaryto a collector. A schematic of an electrospinning nozzle-type device isshown in FIG. 20. A voltage is applied to the polymer solution whichcauses a fine stream of the polymer solution to be drawn towards agrounded collector. The fine stream dries to form polymeric fibers whichbuild up a three dimensional fibrous web structure on the collector.Electrospinning can be used to apply a nanofiber polymer coating onto asubstrate such as a microporous membrane.

In accordance with selected embodiments, at least one object of thepresent invention is to provide a high melt temperature electrospuncoated microporous Lithium-ion rechargeable battery separator ormembrane that is capable of retaining its physical structure up to 250deg C. in a Lithium-ion rechargeable battery (cell, pack, battery,accumulator, capacitor, or the like) for at least a short period oftime. This particular possibly preferred separator or membranepreferably has an electrospun nanofiber coating of polybenzimidazole(PBI) or a blend of PBI with another polymer or polymers applied to atleast one side thereof and preferably coated on two sides of amicroporous base membrane. The electrospun nanofiber coating preferablyconsists of nanoscale PBI fibers which are in the range of 10 to 2,000nanometers in diameter, preferably 20 to 1,000 nanometers in diameter,more preferably 25 to 800 nanometers in diameter, and most preferably 30to 600 nanometers in diameter as shown in the Scanning ElectronMicroscopy (SEM) micrographs in FIGS. 21 and 22. The targeted basisweight of the nanoscale PBI electrospun coating of the high melttemperature microporous Lithium-ion rechargeable battery separatormembrane is 1.0 to 8.0 g/m² or more, preferably 2.0 to 6.0 g/m², morepreferably 2.2 to 5.0 g/m², and most preferably 2.5 to 5.0 g/m².

The results of Hot Electrical (Hot ER) Resistance testing, theExtension-Thermogravimetric Analysis (e-TMA) testing and Hot Tip HolePropagation testing were used to define the high melt temperatureintegrity (HTMI) performance of the inventive electrospun coatedmicroporous Lithium-ion rechargeable battery separator membrane.

FIG. 2 shows a typical Hot ER thermogram showing initial shutdown of atest sample indicated by a sudden increase in Resistance and shows theshutdown integrity window as a flat section of the thermogram whereResistance is sustained at a high level. FIG. 26 shows Hot ER testresults of the inventive PBI one side coated separator and test resultsof a two sided PBI coated separator membrane. At a temperature ofapproximately 135 deg C., the pores in the PE layer of the Celgard® M824PP/PE/PP multilayer base membrane melt and close and the base membraneundergoes thermal shutdown. The Hot ER test indicates thermal shutdownhas occurred in the base membrane with a sharp increase in electricalresistance. As the temperature is increased in the Hot ER test, the oneand two side PBI coated M824 membranes have a sustained increasedelectrical resistance up to a temperature of 200 deg C. indicating thehigh melt temperature integrity of the inventive separator membrane. Thehigh level of sustained increased electrical resistance is indicativethat the separator membrane may prevent electrode shorting in a batterybeyond 200 deg C.

FIG. 27 shows the Extension-Thermogravimetric Analysis (e-TMA) testresults on the inventive electrospun coated separator membrane where thebase membrane ruptures approximately in the region of 160-170 deg C. dueto the melting of the PP layer in the multilater PP/PE/PP base membraneCelgard®M824 and as the temperature is increased, the dimension of themembrane sample remains at 100% up to 250 deg C. The dimension of thetest sample remaining at 100% indicates that the PBI layer is thermallystable up to 250 deg C. This e-TMA performance indicates that theinventive separator has high temperature melt integrity (HTMI) up to atemperature of 250 deg C.

The test results of the Hot Tip Hole Propagation testing show that thediameter of the hole size of the electrospun coated one side PBI and twoside PBI coated samples after contact with a hot tip probe at atemperature of 450 deg C., are 0.6 to 0.7 mm in size while the diameterof the hole size of the uncoated control sample is 2.96 mm. The Hot TipHole Propagation results indicate that the PBI electrospun coatedseparator membrane has high temperature stability in the X, Y and Zdirections. Minimal hole propagation in response to contact with the hottip probe simulates the desired response of the separator membrane to alocalized hot spot which may occur during an internal short circuit inLi-ion cells.

The electrospinning process can deposit nanoscale PBI fibers on thesurface of a base microporous membrane, film, or composite in a randomfashion building a three dimensional nanoscale fibrous web structure onthe base microporous membrane. The fibers have a smooth surfaceappearance when viewed by SEM at 5,000× magnification and arenon-porous, that is, the fibers do not have any pores or holes.

The electrospinning coating approach can coat a high Tg polymer such asPBI or a blend of PBI and another polymer or polymers such aspolyaramids, polyimides and polyamideimide and blends, mixtures and/orcombinations thereof onto a microporous porous membrane without andetrimental affect to the pore structure or the porosity of the porousbase membrane, that is, the nanoscale electrospun fibers do not blockthe pores of the base membrane. The electrospinning process provides amethod of applying a high Tg polymer in the form of nanoscale fibersonto a microporous base membrane without the nanoscale fibers themselvesbeing porous. The spaces between the fibers provide the desiredporosity. Therefore an additional process step to form pores in theelectrospun nanoscale high Tg polymer fibers is not required. In theelectrospinning process the high Tg polymers or polymers are dissolvedin a solvent or solvents. The solvent is evaporated during the formationof the electrospun fibers. Typically, dip coated or gravure coatedmethods of applying polymers onto a microporous base membrane mayrequire the coated film to be immersed in a bath designed for removingor extracting the polymer solvent. This immersion step forms a porousstructure in the coating. The present electrospinning method of applyinghigh Tg polymers onto microporous membranes can be simpler from amanufacturing point of view due to the fact that an extraction orimmersion step to remove the solvent and form pores in the coating isnot required. Electrospinning can be a less costly manufacturing processfor the application of nanoscale high Tg polymer fibers onto amicroporous membrane, film, composite, or carrier to produce a high melttemperature microporous Lithium-ion rechargeable battery separator,membrane, composite, or the like.

EXAMPLE 1

A 13 um Celgard® EK1321 PE microporous membrane was coated with a 4 μmcoating layer consisting of Polybenzimidazole (available as a 26% dopein DMAc from PBI Performance Products in Rock Hill, S.C.) and Degussafumed Alumina 20 nm diameter particles. The coating solution is preparedby first drying the Alumina particles in a 180 deg C. oven overnight toremove moisture. A 25% by weight slurry of the dried Alumina particlesin DMAc is then prepared. The final coating composition is 7%polybenzimidazole (PBI), 28% Alumina and 65% DMAc. The coating isapplied with a slot die as a single sided coating and the coatedmembrane dried in an oven at 80-100 deg C. for a time period of lessthan 15 minutes.

EXAMPLE 2

A 13 um Celgard® EK1321 PE microporous membrane was coated with a 7 μmcoating layer consisting of Polybenzimidazole (available through PBIPerformance Products in Rock Hill, S.C.) and Degussa fumed Alumina 20 nmdiameter particles. The coating solution is prepared by first drying theAlumina particles a 180 deg C. oven overnight to remove moisture. A 25%by weight slurry of the dried Alumina particles in DMAc is thenprepared. The final coating composition is 7% polybenzimidazole (PBI),28% Alumina and 65% DMAc. The coating is applied with a slot die as asingle sided coating and the coated membrane dried in an oven at 80-100deg C. for a time period of less than 15 minutes.

EXAMPLE 3

A 13.3% PBI dope was diluted to 7% with DMAc. This coating solution wasapplied to the 13 um Celgard® EK1321 PE microporous membrane using areverse gravure coating method followed by immersion of the coatedmembrane into a room temperature water bath. The membrane was dried inan oven at 80-100 deg C. for 6-10 minutes. The water bath was designedas a circulating bath in order to minimize the concentration of theDMAc. The membrane coating path was designed so that the coated side ofthe membrane did not come into contact with a roller while in the bath.Immersion time in the bath was at least 1 minute.

EXAMPLE 4

A 13.3% PBI dope was diluted to 7% with DMAc. This coating solution wasapplied to the 13 um Celgard® EK1321 PE microporous membrane using areverse gravure coating method followed by immersion of the coatedmembrane into a 33% Propylene glycol in water bath at room temperature.The membrane was dried in an oven at 80-100 deg C. for 6-10 minutes. Themembrane coating path was designed so that the coated side of themembrane did not come into contact with a roller while in the bath.Immersion time in the bath was at least 1 minute.

EXAMPLE 5

A 26% PBI dope was diluted to 10% in DMAc. This coating solution wasapplied to the 13 um Celgard® EK1321 PE microporous membrane using adoctor blade followed by immersion of the coated membrane into a roomtemperature acetone bath for 3-5 minutes. The membrane was dried in anoven at 100 deg C. for 5 minutes.

EXAMPLE 6

A 16 um Polyethlyene Celgard® separator membrane was coated with aslurry consisting of a polyaramide dissolved in DMAc mixed with Degussafumed Alumina 20 nm particles. The coating was applied using a gravurecoating method.

TABLE 1 Separator Membrane Properties of 13 μm Control Sample andpresent Examples 1-5. Control Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Base FilmThickness (um) 13 13 13 13 13 Base Film type PE PE PE PE PE PE CoatingThickness (um) 4 7 6 6 7 Total Thickness (um) 13 17 20 19 20 20 JISGurley (s) 212 237 261 437 1106 Puncture Strength (g) 329 502 502 542563 Tensile Strength in MD (kgf/cm2) 1824 1251 1262 1449 1568 TensileStrength in TD (kgf/cm2) 996 951 809 948 909 ER (ohms-cm2) 1.1-1.3 1.71.9 2.5 2.9 MD Shrinkage at 120 C./1 hr 8.61 6.22 5.28 2.97 2.41 TDShrinkage at 120 C./1 hr 3.4 0 0.45 0.78 1.37 MD Shrinkage at 130 C./1hr 20.91 11.87 9.76 3.54 3.6 TD Shrinkage at 130 C./1 hr 16.53 6.45 4.391.16 2.14 Hot-Tip Propagation Diameter (mm) 2.43 2.8 3.5 0.63 0.7 <1e-TMA Rupture Temperature (° C.) 145 154 154 215 220 >250

TABLE 2 Separator Membrane Properties of 16 μm and 13 μm Control Samplesand present Examples 6 and 2. PE PE Control Control Property (16 um)Example 6 Example 2 (13 um) Thickness (um) 16 24 17 13 (13 um base film)Dielectric Breakdown (V) 2057 2893 2141 1178 Puncture Strength (g) 516581 502 329 Tensile Strength - MD 1355 1023 1262 1824 kgf/cm2 TensileStrength - TD 1145 1056 809 996 kgf/cm2

EXAMPLE 7

Celgard® M824 Trilayer microporous membrane is electrospun coated on oneside with a 15% solution of Polybenzimidazole (PBI) (available as 26%dope from PBI Performance products in Rock Hill, S.C.) withDimethylacetamide (DMAc) as the solvent. Coating process used a nozzletype electrospinning device where the applied voltage is 15 kV, the flowrate is 0.5 ml/h, the gauge of the needle is 7″ ID, 0.025″ OD and thedistance between the needle tip and the collector is 25 cm. Thethickness of the coating applied to one side of the M824 base membraneis 7-8 μm. The total thickness of the coated sample is 20 μm.

EXAMPLE 8

Celgard® M824 Trilayer microporous membrane is electrospun coated onboth sides with a 15% solution of Polybenzimidazole (PBI) (available as26% dope from PBI Performance products in Rock Hill, S.C.) withDimethylacetamide (DMAc) as the solvent. Coating process used a nozzletype electrospinning device where the applied voltage is 15 kV, the flowrate is 0.5 ml/h, the gauge of the needle is 7″ ID, 0.025″ OD and thedistance between the needle tip and the collector is 25 cm. The basisweight of the coated sample is 0.94 mg/cm². A 3-4 μm thick coating isapplied to each side of the M824 base membrane. The total thickness ofthe coated sample is 20 μm.

EXAMPLE 9

Celgard® 3401 surfactant coated monolayer polypropylene microporousmembrane is electrospun coated on both sides with a 15% solution ofPolybenzimidazole (PBI) (available as 26% dope from PBI Performanceproducts in Rock Hill, S.C.) with Dimethylacetamide (DMAc) as thesolvent. Coating process used a nozzle type electrospinning device wherethe applied voltage is 15 kV, the flow rate is 0.5 ml/h, the gauge ofthe needle is 7″ ID, 0.025″ OD and the distance between the needle tipand the collector is 25 cm. The total thickness of the coated sample is55 μm.

TABLE 3 HTMI Test Data on Control Trilayer M824 Sample and 1-Sided PBIcoated and 2-Sided PBI Coated Celgard Trilayer Base Membrane. M824Control PP/PE/PP Trilayer 1-sided PBI Coated 2-sided PBI Coatedthickness, um 12.0 19.3 20.2 puncture strength, g 259.8 267.4 218.2Basis Weight 0.71 0.91 0.94 mg/cm2 ER (ohm-cm2) 1.67 1.99 2.98 Hot tip,um spot 1 3.0 0.6 0.78 spot 2 3.0 0.6 0.6 spot 3 3.1 0.6 0.6 Hot ERshutdown at 135 deg C. Base PE layer shutdown at 135 Base PE layershutdown at 135 deg C., PBI sustained shutdown at deg C., PBI layersustained 200 deg C. Resistance up to 200 deg C. e-TMA PE layer rupturedat PE base layer ruptured at 135 PE base layer ruptured at 135 135 degC., PP layer deg C., PP base layer ruptured at deg C., PP base layerruptured ruptured at 165 deg C. 165 deg C., PBI caused shift in line at165 deg C., PBI layer did not at 200 deg C. rupture and maintainedstructural integrity up to 250 deg C.

TABLE 4 HTMI Test Data on Control Trilayer Celgard ® 3401 Sample and2-Sided PBI Coated Celgard ® 3401. 3401 Control Monolayer PP 2-sided PBICoated thickness, 26 55 um Basis 1.56 2.22 Weight mg/cm2 Hot tip, 3.81.6 um spot 1 spot 2 4.2 1.3 spot 3 3.7 0.5 Hot ER Base PP membrane BasePP membrane melted at 165 melted at 165 deg C., PBI layer sustainedResistance deg C. up to 200 deg C. e-TMA Base PP membrane Base PPmembrane ruptured at 165-170 ruptured at deg C., PBI layer did notrupture up to 165-170 deg C. 250 deg C.Test Procedures

Thickness: Thickness is measured using the Emveco Microgage 210-Aprecision micrometer according to ASTM D374. Thickness values arereported in units of micrometers (μm).

Gurley: Gurley is defined as the Japanese Industrial Standard (JISGurley) and is measured using the OHKEN permeability tester. JIS Gurleyis defined as the time in seconds required for 100 cc of air to passthrough one square inch of film at a constant pressure of 4.9 inches ofwater.

Tensile Properties Machine Direction (MD) and Transverse Direction (TD)tensile strength is measured using Instron Model 4201 according toASTM-882 procedure.

Puncture strength: Puncture strength is measured using Instron Model4442 based on ASTM D3763. The measurements are made across the width ofmicroporous stretched product and the average puncture strength isdefined as the force required to puncture the test sample.

Shrinkage: Shrinkage is measured at two temperatures by placing a samplein an oven at 120 deg C. for 1 hour and placing a second sample in anoven at 130 deg C. for 1 hour. Shrinkage has been measured in bothMachine Direction (MD) and Transverse Direction (TD).

Basis Weight: Basis weight is determined using ASTM D3776 and the unitsare in mg/cm².

Hot Tip Hole Propagation test: In the Hot Tip hole propagation test ahot tip probe at a temperature of 450 deg C. with a tip diameter of 0.5mm is touched to the surface of the separator membrane. The hot tipprobe approaches the membrane at a speed of 10 mm/minute and is allowedto contact the surface of the separator membrane for period of 10seconds. Results of the hot tip test are presented as a digital imagetaken with an optical microscope showing both the shape of the holeformed as a result of the response of the separator membrane to the 450deg C. hot tip probe and the diameter of the hole in the separatormembrane after the hot tip probe is removed. Minimal propagation of ahole in the separator membrane from contact with the hot tip probesimulates the desired response of the separator membrane to a localizedhot spot which may occur during an internal short circuit in Li-ioncells.

ER (Electrical Resistance): The units of electrical resistance areohm-cm². The separator resistance is characterized by cutting smallpieces of separators from the finished material and then placing thembetween two blocking electrodes. The separators are saturated with thebattery electrolyte with 1.0 M LiPF₆ salt in EC/EMC solvent of 3:7 ratioby volume. The Resistance, R, in Ohms (Ω), of the separator is measuredby a 4-probe AC impedance technique. In order to reduce the measurementerror on the electrode/separator interface, multiple measurements areneeded by adding more layers. Based on the multiple layer measurements,the electric (ionic) resistance, R_(s) (Ω), of the separator saturatedwith electrolyte is then calculated by the formula R_(s)=p_(s)1/A wherep_(s) is the ionic resistivity of the separator in Ω-cm, A is theelectrode area in cm² and 1 is the thickness of the separator in cm. Theratio p_(s)/A=is the slope calculated for the variation of the separatorresistance (ΔR) with multiple layers (Δδ) which is given byslope=p_(s)/A=ΔR/Δδ.

e-TMA: Expansion-Thermomechanical Analysis method measures thedimensional change of a separator membrane under load in the X (Machinedirection) and Y (Transverse direction) directions as a function oftemperature. A sample size of 5-10 mm in length and 5 cm in width isheld in mini-Instron-type grips with the sample under constant 1 gramtension load. The temperature is ramped at 5 deg C./minute until thefilm reaches its melt rupture temperature. Typically, upon raising thetemperature, separators held under tension show shrinkage, then start toelongate and finally break. The shrinkage of separator is indicated by asharp dip downward in the curve. The increase in the dimension indicatesthe softening temperature and the temperature at which the separatorbreaks apart is the rupture temperature.

Hot ER: Hot Electrical Resistance is a measure of resistance ofseparator film while the temperature is linearly increased. The rise inresistance measured as impedance corresponds to a collapse in porestructure due to melting or “shutdown” of the separator membrane. Thedrop in resistance corresponds to opening of the separator due tocoalescence of the polymer; this phenomenon is referred to as a loss in“melt integrity”. When a separator membrane has a sustained high levelof electrical resistance beyond 200 deg C., this is indicative that theseparator membrane may prevent electrode shorting in a battery beyond200 deg C.

In accordance with at least selected embodiments of the presentinvention, one may use the above tests and/or properties of Tables 1 and2 to measure or test a potential high temperature separator or compositeto see if it may be or may qualify as a high temperature melt integrity(HTMI) separator. If it passes the above tests, then, one may test theseparator in a battery, cell or pack to be certain it is a hightemperature melt integrity (HTMI) separator and that it preferably willat least keep the electrodes separated at a temperature of at leastabout 160 deg C., preferably at least 180 deg C., more preferably atleast 200 deg C., still more preferably at least 220 deg C., and mostpreferably at least 250 deg C.

In accordance with at least selected embodiments of the presentinvention, if the high temperature separator passes the above tests ofTables 1 and 2, this is a good indicator that the separator may be ormay qualify as a high temperature melt integrity (HTMI) separator.

In accordance with at least a selected embodiment of the presentinvention, a good indicator or initial test procedure to see if aseparator may be used as or may qualify as a high temperature meltintegrity (HTMI) battery separator, includes the steps of:

-   -   1) running the above separator Thickness, Gurley, Tensile,        Puncture, Shrinkage, Hot Tip, ER, e-TMA, and Hot ER tests on the        separator, and if it passes, then    -   2) running cell or battery tests on the separator to be certain.

In accordance with at least a selected embodiment of the presentinvention, one may measure or test a high temperature polymer, filler,coating, layer, or separator to see if it may be or may qualify for usein or as a high temperature separator or as a high temperature meltintegrity (HTMI) coating, layer or separator, by the method of:

-   -   1) checking the polymer (or polymers) and filler (or fillers, if        any) of the high temperature coating, layer or stand alone        separator to see that they each have a melt temperature or        degradation temperature of at least about 160 deg C., preferably        at least 180 deg C., more preferably at least 200 deg C., still        more preferably 220 deg C., and most preferably at least 250 deg        C.;    -   2) checking the polymer (or polymers) and filler (if any) of the        high temperature coating, layer or stand alone separator to see        that they each do not dissolve in the electrolyte of the        intended battery for the separator;    -   3) measuring the shrinkage of the stand alone or complete        separator (including the high temperature coatings or layers) to        ensure it is less than about 15% at 150 deg C., preferably less        than 10% at 150 deg C., more preferably less than 7.5% at 150        deg C., and most preferably less than 5% at 150 deg C.; and,    -   4) if the high temperature coating, layer, stand alone        separator, and complete separator pass the three tests above,        then, testing the stand alone or complete separator in a        battery, cell or pack to be certain it is a high melt        temperature separator or high temperature melt integrity (HTMI)        separator and that it will at least keep the electrodes        separated at a temperature of at least about 160 deg C.,        preferably at least 180 deg C., more preferably at least 200 deg        C., still more preferably at least 220 deg C., and most        preferably at least 250 deg C.

If the high temperature coating, layer, stand alone separator, andcomplete separator pass the three tests above, this is a good indicatorthat the stand alone or complete separator (including the hightemperature coatings or layers) may be or may qualify as a high melttemperature separator or high temperature melt integrity (HTMI)separator, but to be certain the stand alone or complete separatorshould be tested in a battery, cell, or pack.

In accordance with at least a selected embodiment of the presentinvention, a good indicator or initial test to see if a high temperaturecoating, layer or stand alone high temperature separator may be used as,may be used in, or may qualify as a high melt temperature separator orhigh temperature melt integrity (HTMI) coating, layer or separator,includes the steps of:

-   -   1) checking the polymer (or polymers) and filler (if any) of the        high temperature coating, layer or stand alone separator to see        that they each have a melt temperature, degradation temperature,        melting point, decomposition temperature, or Tg of at least        about 180 deg C., preferably at least 200 deg C., more        preferably at least 220 deg C., and most preferably at least 250        deg C.;    -   2) checking the polymer (or polymers) and filler (if any) of the        high temperature coating, layer or stand alone separator to see        that they each do not dissolve in the electrolyte of the        intended battery for the separator; and,    -   3) measuring the shrinkage of the stand alone or complete        separator (including the high temperature coatings or layers) to        ensure the shrinkage is less than about 15% at 150 deg C.,        preferably less than 10% at 150 deg C., more preferably less        than 7.5% at 150 deg C., and most preferably less than 5% at 150        deg C.

If the high temperature coating, layer, stand alone separator, andcomplete separator pass the three tests above, this is a good indicatoror initial test that the high temperature coating, layer, stand aloneseparator, or complete separator may be used as, may be used in, or mayqualify as a high melt temperature separator or high temperature meltintegrity (HTMI) coating, layer or separator, and that the separator mayat least keep the electrodes separated at a temperature of at leastabout 160 deg C., preferably at least 180 deg C., more preferably atleast 200 deg C., still more preferably at least 220 deg C., and mostpreferably at least 250 deg C. To be certain, one should test the standalone or complete separator in a battery, cell or pack.

Adding filler or particles to the high temperature polymer coating orlayer can make it easier to form pores as the spaces or voids betweenthe filler or particles help form the pores, may reduce cost, etc.However, adding filler or particles to the high temperature polymercoating material or batch can make polymer processing more difficult. Assuch it is possibly preferred to not add filler or particles to keep theprocessing simpler and to use the bath (see FIG. 1) to form the pores.

As the HTMI separator need only keep the electrodes separated for ashort time, in accordance with at least certain embodiments of theinvention, one may use a high Tg polymer, a polymer or material thatdoes not melt, a polymer or material that melts or flows slowly, across-linked polymer or material, or other material, blend or mixturethat will keep the electrodes separated long enough to allow the batterycontrol circuitry to shut off the battery.

In at least one embodiment, there is provided a separator with a highmelt temperature, preferably >160 deg C. and more preferably >180 degC., that has the high level of dimensional and/or structural integrityneeded to prevent contact between the anode and cathode when the batteryis maintained at elevated temperatures for a period of time. In thisembodiment, it is highly desirable to have such a separator with a highlevel of dimensional and structural integrity. Such a separator isreferred to as a high temperature melt integrity (HTMI) separator. Thisseparator is a high melt temperature battery separator including aporous membrane, film or base coated with a high glass transitiontemperature (Tg) polymer (also referred to as a binder).

In at least another embodiment, there is provided a stand alone porousmembrane made using a high Tg polymer. This high temperature separatorhas a high melt temperature, preferably >160 deg C. and morepreferably >180 deg C., has a high level of dimensional and/orstructural integrity needed to prevent contact between the anode andcathode when the battery is maintained at elevated temperatures for aperiod of time, and may shut-down or may allow for ionic flow betweenthe anode and cathode when the battery is maintained at elevatedtemperatures for a period of time. In this embodiment, it is highlydesirable to have such a separator with a high level of dimensional andstructural integrity. Such a separator is referred to as a hightemperature melt integrity (HTMI) separator with or without shutdown.This separator preferably does not melt or melt down, and may continueto partially or fully function at high temperatures.

At least selected embodiments are directed to:

-   -   A high melt temperature microporous Lithium-ion rechargeable        battery separator, separator membrane, and the like that        preferably prevents contact between the anode and cathode when        the battery is maintained at elevated temperatures for a period        of time.    -   A method of making or using one or more high melt temperature        microporous Lithium-ion rechargeable battery separators,        separator membranes, and the like that preferably prevent        contact between the anode and cathode when the battery is        maintained at elevated temperatures for a period of time.

A Lithium-ion rechargeable battery including one or more high melttemperature microporous Lithium-ion rechargeable battery separators,separator membranes, and the like (with or without shutdown) thatpreferably prevent contact between the anode and cathode when thebattery is maintained at elevated temperatures for a period of time.

A shutdown Lithium-ion rechargeable battery separator that thatpreferably prevents contact between the anode and cathode when thebattery is maintained at elevated temperatures for a period of time.

A Lithium-ion rechargeable battery, cell, pack, accumulator, capacitor,or the like including one or more high melt temperature separators,separator membranes, and the like, that preferably prevents contactbetween the anode and cathode when the battery is maintained at elevatedtemperatures for a period of time, and wherein the battery, cell, pack,or the like may be of any shape, size and/or configuration, such ascylindrical, flat, rectangular, large scale Electric Vehicle (EV),prismatic, button, envelope, box, and/or the like.

A separator, separator membrane, or the like for a Lithium-ionrechargeable battery that is capable of at least partial functioning athigh temperatures, for example, at about 160 deg C. or more, at about180 deg C. or more, or higher, for at least a short period of time,wherein the partial functioning includes keeping the electrodes (anodeand cathode) physically separated.

A high melt temperature separator that shuts down at about 130 deg C.,but keeps the electrodes (anode and cathode) physically separated atabout 160 deg C.

A microporous battery separator that includes at least one layer orcomponent having a high melt temperature.

A high temperature separator having a high melt temperature,preferably >160 deg C. and more preferably >180 deg C., and having ahigh level of dimensional or structural integrity needed to preventcontact between the anode and cathode when the battery is maintained atelevated temperatures for a period of time.

A high temperature melt integrity (HTMI) separator with a high level ofdimensional or structural integrity.

A high melt temperature battery separator including a porous membranecoated with a high glass transition temperature (Tg) polymer or blend(also referred to as a binder) on at least one side thereof.

A stand alone (single or multi-ply) porous membrane made using a high Tgpolymer or blend.

A high melt temperature microporous Lithium-ion rechargeable batteryseparator or membrane that is capable of retaining its physicalstructure up to 250 deg C. in a Lithium-ion rechargeable battery (cell,pack, battery, accumulator, capacitor, or the like).

The separator or membrane above, composed of one or more polymers whichhave a glass transition temperature (T_(g)) greater than 165 deg C.,preferably greater than 180 deg C., more preferably at least 250 deg C.,and which is soluble in at least one moderately volatile solvent.

The separator or membrane above, composed of a single or double sidedhigh Tg polymer coating applied to a microporous base membrane or of afree standing high Tg polymer microporous separator or membrane.

The separator or membrane above, with the high Tg polymer coated onto amicroporous base membrane made of a thermoplastic polymer, thethermoplastic polymers include, but are not limited to, polyolefins suchas polyethylene, polypropylene, polymethylpentene, and blends, mixtures,or combinations thereof.

The separator or membrane above, wherein such microporous base membranesare manufactured by a dry stretch process (known as the Celgard® drystretch process), by a wet process also known as a phase separation orextraction process, by a particle stretch process, or the like.

The separator or membrane above, wherein the base membrane may be asingle layer (one or more plies) or multi-layer membrane, such as atri-layer membrane e.g., Polypropylene/Polyethylene/Polypropylene(PP/PE/PP) or Polyethylene/Polypropylene/Polyethylene (PE/PP/PE),bi-layer membrane (PP/PE or PE/PP), or the like.

The separator or membrane above, wherein the base membrane or film, suchas Polypropylene, may optionally be pre-treated in order to alter thesurface characteristics of the membrane and improve the adhesion of thehigh Tg polymer coating to the base membrane.

The separator or membrane above, wherein the pre-treatments may include,but are not limited to, priming, stretching, corona treatment, plasmatreatment, and/or coating, such as surfactant coatings on one or bothsides thereof.

The separator or membrane above, wherein the high Tg polymer may beapplied by a coating step followed by an immersion step, and wherein thehigh Tg coated membrane is immersed into a gelation bath to bothprecipitate the high Tg polymer and to remove the solvent for high Tgpolymer in order to form a high Tg porous coating or layer.

The separator or membrane above, wherein the high Tg polymer may beapplied by a coating step followed by an immersion step wherein the highTg coated membrane is immersed into a bath to precipitate the high Tgpolymer.

The separator or membrane above, wherein the high Tg polymer ispolybenzimidazole (PBI). The separator or membrane above, wherein thehigh temperature coating or layer comprises polybenzimidazole (PBI) andfumed Alumina.

The separator or membrane above, wherein the coating was applied as acoating solution or slurry of PBI, Alumina particles, and DMAc.

A high melt temperature electrospun coated microporous Lithium-ionrechargeable battery separator, separator membrane, and the like thatpreferably prevents contact between the anode and cathode when thebattery is maintained at elevated temperatures for a period of time.

A method of making or using one or more high melt temperatureelectrospun coated microporous Lithium-ion rechargeable batteryseparators, separator membranes, and the like that preferably preventcontact between the anode and cathode when the battery is maintained atelevated temperatures for a period of time.

A Lithium-ion rechargeable battery including one or more high melttemperature electrospun coated microporous Lithium-ion rechargeablebattery separators, separator membranes, and the like that preferablyprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time.

A Lithium-ion rechargeable battery that is capable of functioning athigh temperatures, preferably including components such as anelectrospun coated microporous battery separator or separator membranethat preferably functions at high temperatures.

An improved electrospun battery separator for at least certain hightemperature applications, for a high melt temperature electrospun coatedmicroporous Lithium-ion rechargeable battery separator, separatormembrane, and the like that preferably prevents contact between theanode and cathode when the battery is maintained at elevatedtemperatures for a period of time, for methods of making and/or usingsuch separators, separator membranes, and the like, and/or forLithium-ion rechargeable batteries including one or more suchseparators, separator membranes, and the like.

A Lithium-ion rechargeable battery, cell, pack, accumulator, capacitor,or the like including one or more high temperature electrospun coatedseparators, separator membranes, and the like, wherein the Lithium-ionrechargeable battery, cell, pack, or the like may be of any shape, sizeand/or configuration, such as cylindrical, flat, rectangular, largescale Electric Vehicle (EV), prismatic, button, envelope, box, and/orthe like.

An electrospun coated separator, separator membrane, or the like for aLithium-ion rechargeable battery that is capable of functioning at hightemperatures, for example, at about 160 deg C. or more, at about 180 degC. or more, or higher, for at least a short period of time, wherein“functioning” may include keeping the electrodes (anode and cathode)physically separated, allowing ionic flow between the electrodes, orboth.

An electrospun coated high temperature separator that shuts down atabout 130 deg C., but keeps the electrodes (anode and cathode)physically separated at about 160 deg C., that allows ionic flow betweenthe electrodes at about 160 deg C. (does not shutdown at 130 deg C.), orboth.

An electrospun coated microporous battery separator that functions athigh temperatures, does not melt at high temperatures, has a high melttemperature, includes at least one layer or component having a high melttemperature, and/or the like.

An electrospun coated high temperature separator having a high melttemperature, preferably >160 deg C. and more preferably >180 deg C., andhaving a high level of dimensional or structural integrity needed toprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time.

An electrospun coated high temperature melt integrity (HTMI) separatorwith a high level of dimensional or structural integrity.

A high melt temperature microporous Lithium-ion rechargeable batteryseparator or membrane that is electrospun coated with a PBI on at leastone side thereof.

The electrospun coated separator or membrane above composed of a singleor double sided PBI electrospun coating applied to a microporous basemembrane.

The electrospun coating above that consists of PBI or a blend of PBIwith one or polymers including polyamides, polyaramids, polyimides,polyamideimides, polyvinylidene fluoride or co-polymers ofpolyvinylidene fluoride and blends, mixtures and/or combinationsthereof.

The electrospun coating above that is composed of PBI that is at least 4μm in thickness, preferably at least 5 μm in thickness, more preferablyat least 6 μm in thickness, and most preferably at least 7 μm inthickness.

The electrospun coating above that is composed of PBI or a blend of PBIwith one or polymers including polyamides, polyaramids, polyimides,polyamideimides, polyvinylidene fluoride or co-polymers ofpolyvinylidene fluoride and blends, mixtures and/or combinations thereofthat is at least that is at least 4 μm in thickness, preferably at least5 μm in thickness, more preferably at least 6 μm in thickness, and mostpreferably at least 7 μm in thickness.

The electrospun coating above that is composed of PBI or a blend of PBIwith one or polymers including polyamides, polyaramids, polyimides,polyamideimides, polyvinylidene fluoride or co-polymers ofpolyvinylidene fluoride and blends, mixtures and/or combinations thereofthat has an Add-on of at least 2.0 to 6.0 g/m², more preferably 2.2 to5.0 g/m², and most preferably 2.5 to 5.0 g/m².

The separator or membrane above with the PBI electrospun coated onto amicroporous base membrane made of a thermoplastic polymer, thethermoplastic polymers include, but are not limited to, polyolefins suchas polyethylene, polypropylene, polymethylpentene, and blends, mixtures,or combinations thereof.

The separator or membrane above having such microporous base membranesmanufactured by a dry stretch process (known as the Celgard® dry stretchprocess), by a wet process also known as a phase separation orextraction process, by a particle stretch process, or the like.

The separator or membrane above wherein the base membrane may be asingle layer polypropylene or polyethylene (one or more plies) ormulti-layer membrane, such as a tri-layer membrane e.g.,Polypropylene/Polyethylene/Polypropylene (PP/PE/PP) orPolyethylene/Polypropylene/Polyethylene (PE/PP/PE), bi-layer membrane(PP/PE or PE/PP), or the like. The separator or membrane above whereinthe base membrane or film, such as Polypropylene, may optionally bepre-treated in order to alter the surface characteristics of themembrane and improve the adhesion of the electrospun PBI coating to thebase membrane.

The separator or membrane above wherein the pre-treatments may include,but are not limited to, priming, stretching, corona treatment, plasmatreatment, and/or coating, such as surfactant coating(s) on one or bothsides thereof.

Disclosed or provided are high melt temperature microporous Lithium-ionrechargeable battery separators, shutdown high melt temperature batteryseparators, battery separators, membranes, composites, and the like thatpreferably prevent contact between the anode and cathode when thebattery is maintained at elevated temperatures for a period of time,methods of making, testing and/or using such separators, membranes,composites, and the like, and/or batteries, Lithium-ion rechargeablebatteries, and the like including one or more such separators,membranes, composites, and the like.

High melt temperature microporous battery separators, shutdown high melttemperature battery separators, battery separators, membranes, films,composites, coatings, layers, components, and the like that preferablyprevent contact between the anode and cathode when the battery ismaintained at elevated temperatures for a period of time, methods ofmaking, testing and/or using such separators, membranes, films,composites, coatings, layers, components, and the like, and/orbatteries, Lithium-ion rechargeable batteries, and the like includingone or more such separators, membranes, films, composites, coatings,layers, components, and the like as claimed, shown or described herein.

The invention is not limited by the above description or examples.

The invention claimed is:
 1. A high melt temperature microporous batteryseparator for a lithium-ion rechargeable battery comprising: amicroporous membrane, said microporous membrane being a stretchedthermoplastic polymer film or sheet, said thermoplastic polymerconsisting of a polyolefin selected from the group consisting of:polyethylene, polypropylene, polymethylpentene, and combinationsthereof; and a coating on at least one entire side of said microporousmembrane comprising a high glass transition temperature (T_(g)) polymer,wherein said high glass transition temperature (T_(g)) polymer beingpolybenzimidazole (PBI) or blends of PBI with one or more otherpolymers, said coating has a dimensional or structural integrity toprevent contact between an anode and a cathode of the lithium-ionrechargeable battery, and prevents contact between the anode and cathodewhen the lithium-ion rechargeable battery is maintained at elevatedtemperatures for at least a period of time.
 2. The high melt temperaturemicroporous battery separator of claim 1 wherein said high glasstransition temperature (T_(g)) polymer having a glass transitiontemperature (T_(g)) greater than 165° C.
 3. The high melt temperaturemicroporous battery separator of claim 1 wherein said high glasstransition temperature (T_(g)) polymer having a glass transitiontemperature (T_(g)) greater than 180° C.
 4. The high melt temperaturemicroporous battery separator of claim 1 wherein said high glasstransition temperature (T_(g)) polymer having a glass transitiontemperature (T_(g)) of at least 250° C.
 5. The high melt temperaturemicroporous battery separator of claim 1 wherein said high glasstransition temperature (T_(g)) polymer being soluble in at least onevolatile solvent.
 6. The high melt temperature microporous batteryseparator of claim 1 wherein said other polymers being selected from thegroup consisting of: polyimides, polyamideimides, polysulfones,polyketones, and combinations thereof.
 7. The high melt temperaturemicroporous battery separator of claim 1 wherein said coating furthercomprising fumed alumina.
 8. The high melt temperature microporousbattery separator of claim 1, wherein the coating was applied as acoating solution or slurry of PBI, alumina particles, and DMAc.
 9. Thehigh melt temperature microporous battery separator of claim 1, whereinsaid microporous membrane being at least one of a polyolefin membrane, apolypropylene membrane, a polyethylene membrane, and a trilayerseparator.
 10. The high melt temperature microporous battery separatorof claim 1 wherein said microporous membrane being manufactured by a drystretch process or a wet process.
 11. The high melt temperaturemicroporous battery separator of claim 1 wherein said microporousmembrane being a single layer membrane, a bi-layer membrane, a tri-layermembrane, or a multi-layer membrane.
 12. The high melt temperaturemicroporous battery separator of claim 1, wherein said microporousmembrane having a pre-treatment adapted for altering the surfacecharacteristics of the membrane and improving the adhesion of the highT_(g) polymer coating to the membrane, wherein said pre-treatment beingon one or both sides of said microporous membrane and being selectedfrom the group consisting of: priming, stretching, corona treatment,plasma treatment, coating such as surfactant coatings, and combinationsthereof.
 13. The high melt temperature microporous battery separator ofclaim 1, wherein said high T_(g) polymer coating being applied to saidmicroporous membrane by one of: a coating step followed by an immersionstep, and wherein the high T_(g) coated membrane is immersed into agelation bath to both precipitate the high T_(g) polymer and to removethe solvent for high T_(g) polymer in order to form a high T_(g) porouscoating or layer, or a coating step followed by an immersion stepwherein the high T_(g) coated membrane is immersed into a bath toprecipitate the high T_(g) polymer.
 14. The high melt temperaturemicroporous battery separator of claim 1 wherein said battery separatorhaving a melt temperature of >160° C.
 15. The high melt temperaturemicroporous battery separator of claim 1 wherein said battery separatorhaving a melt temperature of >250° C.
 16. The high melt temperaturemicroporous battery separator of claim 1, wherein the coating wasapplied as a plurality of high glass transition temperature (T_(g))polymer nanofibers being electrospun onto at least one side of saidmicroporous membrane.
 17. In a lithium-ion rechargeable battery, theimprovement comprising the high melt temperature microporous batteryseparator of claim
 1. 18. The high melt temperature microporous batteryseparator of claim 1, wherein said coating on at least one side of saidmicroporous membrane comprising a plurality of polymer nanofibers onsaid microporous membrane, said polymer having a glass transitiontemperature (T_(g)) of at least 160° C.
 19. The high melt temperaturemicroporous battery separator of claim 1, wherein said microporousmembrane comprising a polymer or blend, said polymer or blend having aglass transition temperature (T_(g)) of at least 160° C.; whereby, saidmicroporous membrane being capable of retaining its physical structureup to 250° C. in a lithium-ion rechargeable battery, cell, pack,battery, accumulator, or capacitor.
 20. A battery comprising the batteryseparator of claim 1.